Key switch

ABSTRACT

A Hall generator located in a housing of a key switch is actuated to produce a signal by magnetic actuating means carried on a plunger which is movable in an opening of the housing to an actuating position. The plunger is releasably secured to the housing by a pair of resilient holders which are received through corresponding openings in a wall of the plunger, and the plunger is urged from the actuated position to a normal raised position by a coiled compression spring disposed in the housing. The key switch may be converted to a detainable switch by removably securing a detaining spring to the plunger for acting in cooperation with a preformed detaining slot in the housing, and the key switch may be converted to an illuminated switch with the addition of a lamp. The leads of the lamp may be inserted through preformed openings in the plunger and the housing for suitable connections below, and the light produced from the lamp is visible through a transparent cap removably secured to the plunger.

Hermann Dec. 17, 1974 KEY SWITCH [75] Inventor: Hans Hermann, Nuernberg, Germany [73] Assignee: Triumph Werke Nuernberg'A.G.,

Nuernberg, Germany [22] Filed: July 6, 1973 [21] App]. No.: 377,038

[ 30] Foreign Application Priority Data July 6, 1972 Germany 2233170 U [52] US. Cl 200/159 R, 200/160, 3l0/DIG. 3,

338/32 H [51] Int. Cl. H01h 13/64 [58] Field of Search 200/169 PB:159 R, 167 A, 200/153 J, 160; 340/365 L; 338/32 H;

Primary Examiner-William H. Beha, Jr.

Assistant ExaminerHarry E. Moose, Jr. Attorney, Agent, or FirmJoseph R. Spalla [57] ABSTRACT A Hall generator located in a housing of a key switch is actuated to produce a signal by magnetic actuating means carried on a plunger which is movable in an opening of the housing to an actuating position. The plunger is releasably secured to the housing by a pair of resilient holders which are received through corresponding openings in a wall of the plunger, and the plunger is urged from the actuated position to a normal raised position by a coiled compression spring disposed in the housing. The key switch may be converted to'a detainable switch by removably securing a detaining spring to the plunger for acting in cooperation with a preformed detaining slot in the housing, and the key switch may be converted to an illuminated switch with the addition of a lamp. The leads of the lamp may be inserted through preformed openings in the plunger and the housing for suitable connections below, and the light produced from the lamp is visible 'through a transparent cap removably secured to the plunger.

5 Claims, 3 Drawing Figures KEY SWITCH This invention relatesto a key switch for use in a data processing system, and more particularly to a key switch having a depressible plunger which is movable in a housing to actuate an electric switch means to produce a signal.

In data processing equipment, key switches of many different types are often required. For exaple,'in entering data the key switches are only required to provide signals of short duration. In other instances, a signal of longer duration is required and accordingly a detainable key switch is desirable. In still other. applications, it is desirable to provide a key switch which is illuminated upon actuation.

However, to provide a plurality of different types of key switches requires different tooling to produce the switches and requires a larger inventory of parts for both manufacturing and' replacement purposes, because in the typical key switch as shown for example in German Pat. 1,640,273, cannot be altered to perform different functions.

Accordingly, an object of the present invention is to provide akey switch which may be adapted to provide a detainable signal or a visable indicationvof switch actuation. r I

Still other objects, features and advantages of the present invention will be apparent ot those skilled in the art from a reading of the following detailed description of the invention, taken in conjunction with the accompanying drawings wherein:

FIG. 1 shows a diagrammatic perspective view of a key switch constructed in accordance with the present invention; FIG 2 is a partial fragmentary exploded view of the key'switch shown in FIG."l; and

F 16.3 is a diagrammatic view of a portion of the key switch shown'in FIG; 2.

' Referring now in detail to th'e'figures in the drawing, thereis shown a key switch, generally indicated 11, for producing a signal which is usable a data processing To removably secure the plunger 25 in the opening 23 of the housing 15, the housing 15 is provided with with a hook 37 formed on the end for being received in the plunger 25 through a pair of openings 39, 41 formed in a transverse wall 43. The openings 39, 41 are spacedapart a sufficient distance for enabling the plunger to move freely through the opening 23 of the housing 15 but are arranged so as to require the holding members 33, 35 to be flexed relativeto each other before passing through the spaced-apart openings 39, 41. To facilitate the insertion of the upstanding holding members 33, 35 into the plunger 25 as the plunger 25 is placed into the opening 23 of the housing 15, the plunger 25 is provided with a pair of depending legs 45, 47 having beveled end portions 49 for suitably flexing the corresponding holding members '33, 35 toward the openings 39 41 in the transverse wall 43. When the plunger 25 is fully assembled in the housing 15, the depending legs 45, 47 are received in corresponding recesses 51, 53 respectively, formed in the housing 15 and serve to guide the plunger 25 when the key 13 is depressed. In addition, the plunger 25. maybe provided with other depending guide tabs 52 which are received in other suitable recesses 54 in the housing 15.

As previously described, suitable electrical switch means 19 are located insidethe housing 15 of the key switch 11 for producing a signal when the key 13 is depressed. As shown, the switch means 19 is in-the form of a Hall generator having leads 55 which extend through the bottom of the housing 15, and the Hall generator is operated by the actuating means 17 carried by the key 13. The actuating means includes a permanent mangnet 57'suitably secured to a bracket 59 which is suitably'attached to the plunger 25.

As previously mentioned, the key is normally maintained in a raised position by the coiledcompression spring 21, and the coiled spring 21 is positioned in the housing 13 with one of the coiled ends receiving a suitable conical projection 61 formed on the base of the system. The keys'witch l l'hasa depressible key,'generally' indicated 13', whichis movable in a housing 15 which may 'be" placed in a suitable holder, not shown, of an input keyboard, and thekey 13 carries actuating means, generally indicated'l7, for operating'suitable electrical switch means, generally indicated 19, located in the housing 15. The key 13 is norm-allyheld in a raised position by resilient biasing means in the form of a coiled compression spring 21, and upon depression of the key 13 to an actuating position the actuating means so as to produce a signal. To provide a return path for 17 operates the switch means 19 to produce a signal.

the rectangular opening 23 in the housing 15 and an upper inwardly recessed extension 27 on which a cap 29 having a rectangular-shaped collar 31 is suitably secured, for example by friction. As is conventional, the top of the cap 29 may have a suitable finger depression and bear indicia of its associated function.

housing 15'while the other coiled end receives a downwardly bent tip 63 on the bracket 59. When the key13 ismoiied to the actuating positionpthe permanent mag v net is brought alongside the Hall generator to effect a change in electrical condition in awe" known-manner the magnetic flux associated with the magnet 57, the bracket 59 has a bent-over arm 65 with a surface spaced from the magnet 57 so as to be broughtalong the opposite side of the Hall generator.

From the foregoing, it will be apparent that the key switch 11 will produce a signal'only when the key 13 is depressed to an actuating position so as to bring the magneticactuating means 17 into operating proximity I l l n with the Hall generator, and it is further apparent that the signal will be produced only for a'period of time in which the key 13 is manually depressed.

In accordance with one feature of the present invention, the above-described key switch 11 may be easily converted to a detainable switch so as to continue to produce a signal without being manually held in the actuated position. To convert the key switch 11 into a detainable switch, only a detaining spring 67 is added to the above-described key assembly. As shown, the

is inserted through a suitable opening 73 in the transverse wall 43 of the plunger 25. The upper clip portion 69 is removably secured to the extension 27 of the plunger 25 with the end 75 being inserted into a hole 77 formed in the extension 27. The depending end portion 71 has a bent end 79 which is resiliently received in a detaining slot 81 which may be preformed in a suitable inside wall of the housing 15. As more particularly shown in FIG. 3, the detaining slot 81 has a shunt 83 directing the end 79 of the detaining spring 67 into a first portion 85 which leads to a holding detent 87 when the key 13 is depressed to the actuated position. Upon repeated depression of the key 13, the depending end 79 of the detaining spring 67 moves from the holding detent 87 to another portion of the detaining slot 81 leading from the actuating position to enable the key 13 to return to the raised position.

In accordance with another feature of the present invention, the key switch 11 may also be easily converted to provide an illuminated indication of the actuation of the switch. As shown, a lamp 91 may be placed in the housing 15 by inserting the associated lead wires 93 througha suitable opening 95 in the transverse wall 43 of the plunger 25 and through suitable holes 97in the bottom of the housing where they may be connected so as to energize the lamp 91 when the Hall generator is operated. To enable the light from the lamp 9] to be visible to an operator, the cap 13 may be formed from a suitable transparent material.

What is claimed is:

1. A key switch construction convertible from a momentary to a latching switch comprising an upwardly open box-like housing,

a downwardly open box-like plunger telescopically a resilient plunger latching element removably mountable on said plunger whenever conversion from a momentary to a latching switch is desired,

said latching element having an end depending into said housing,

a removable cap on said plunger providing for access into the interior of said plunger for releasing said plunger from said housing for withdrawal therefrom and for mounting said latch element, and

a slot in said housing for guiding the end of said mounted resilient plunger latch element into and out of a detented position respectively in response to a first depression of said plunger to latch the plunger down and to a second depression to release said plunger.

2. A key switch construction as recited in claim 1, said switching element in said housing having receptacles for accommodating wire terminals of a lamp, and said plunger having an opening in a top portion to allow insertion of said lamp wire terminals and to locate a connected lamp beneath the top cover, said top cover having a light transmissive portion.

3. A key switch construction as recited in claim 1, said switching elements mounted in said housing and said plunger respectively comprising a Hall generator and magnetic means acting on said Hall generator when said plunger is depressed.

4. A key switch construction as recited inclaim 3, said magnetic means comprising:

a permanent magnet movable into proximity with said Hall generatorupon depression of said plunger, and r a magnetically conductive bracket secured to said permanent magnet and providing a return path for the flux associated with said magnet.

5. A keyswitch construction as recited in claim 1, said means on said housing and said plunger for releasably latching said plunger against withdrawal comprising a pair of upstanding holding members secured to said housing and extending toward said plunger in the direction of the movement of said plunger,

said pair of holding members being spaced apart and resilient with a hook portion formed on the free end thereof,

said plunger having spaced-apart openings formed therein for receiving said holding members,-

camming means on said plunger for flexing said holding members toward one another for reception through said openings formed in said plunger as the plunger is mounted in said housing and latch said plunger in said housing, and

said holding members serving to guide plunger movement. 

1. A key switch construction convertible from a momentary to a latching switch comprising an upwardly open box-like housing, a downwardly open box-like plunger telescopically mountable for movement in said housing, said plunger and housing having cooperating switching elements mounted thereon, operable to effect switching when said plunger is depressed, a spring mounted in said housing acting on said plunger to maintain it in a raised position and return said plunger following a depression and release of said plunger, means on said housing and plunger for limiting depression of said plunger and releasably latching said plunger against withdrawal from said housing, a resilient plunger latching element removably mountable on said plunger whenever conversion from a momentary to a latching switch is desired, said latching element having an end depending into said housing, a removable cap on said plunger providing for access into the interior of said plunger for releasing said plunger from said housing for withdrawal therefrom and for mounting said latch element, and a slot in said housing for guiding the end of said mounted resilient plunger latch element into and out of a detented position respectively in response to a first depression of said plunger to latch the plunger down and to a second depression to release said plunger.
 2. A key switch construction as recited in claim 1, said switching element in said housing having receptacles for accommodating wire terminals of a lamp, and said plunger having an opening in a top portion to allow insertion of said lamp wire terminals and to locate a connected lamp beneath the top cover, said top cover having a light transmissive portion.
 3. A key switch construction as recited in claim 1, said switching elements mounted in said housing and said plunger respectively comprising a Hall generator and magnetic means acting on said Hall generator when said plunger is depressed.
 4. A key switch construction as recited In claim 3, said magnetic means comprising: a permanent magnet movable into proximity with said Hall generator upon depression of said plunger, and a magnetically conductive bracket secured to said permanent magnet and providing a return path for the flux associated with said magnet.
 5. A key switch construction as recited in claim 1, said means on said housing and said plunger for releasably latching said plunger against withdrawal comprising a pair of upstanding holding members secured to said housing and extending toward said plunger in the direction of the movement of said plunger, said pair of holding members being spaced apart and resilient with a hook portion formed on the free end thereof, said plunger having spaced-apart openings formed therein for receiving said holding members, camming means on said plunger for flexing said holding members toward one another for reception through said openings formed in said plunger as the plunger is mounted in said housing and latch said plunger in said housing, and said holding members serving to guide plunger movement. 